Answer:
Step-by-step explanation:
Given that
Area of a circle 
Circumference of the circle 
Let us re-write the equation of area of circle:


Multiplying and dividing with 2:

Hence, <em>A</em> in terms of <em>C</em> can be represented as:

Answer:
(x − 5) (x + 4)
Step-by-step explanation:
x² − x − 20
Factor using AC method:
1 × -20 = -20
Factors of -20 that add up to -1: -5 and 4
Divide by 1 and reduce: -5/1 and 4/1
(x − 5) (x + 4)
Answer:
31.2
Step-by-step explanation: